Phendimetrazine

BONTRIL

What it isNorepinephrine-releasing sympathomimetic and prodrug of phenmetrazine; brief adjunct for weight management.

Why this oneConversion to phenmetrazine brings substantial stimulant and abuse liability with little role beyond short-term appetite suppression.

What limits itBlood pressure and heart rate rise; avoid cardiovascular disease and MAOIs. Tolerance and dependence limit use.

FDA label

FDA dosing	Population	Start	Target	Max
Obesity (anorectic; indication inferred from Clinical Pharmacology — Indications section not in source data)	Adults	35 mg (1 tab) BID–TID, 1 h before meals; 17.5 mg (½ tab) per dose may be adequate	Lowest effective dose, BID–TID	70 mg TID (2 tabs TID)

Renal Undefined

Hepatic Undefined

Known hypersensitivity or idiosyncratic reactions to sympathomimetics
Advanced arteriosclerosis, symptomatic cardiovascular disease, moderate-severe hypertension, hyperthyroidism, glaucoma
Highly nervous or agitated patients
History of drug abuse
Concurrent other CNS stimulants, including MAOIs

CV: palpitations, tachycardia, elevated BP, ischemic events; valvular heart disease reported with some anorectics (fenfluramine/dexfenfluramine, esp. in combination) — no cases reported with phendimetrazine alone
CNS: overstimulation, restlessness, insomnia, agitation, flushing, tremor, sweating, dizziness, headache, psychotic state, blurred vision
GI: dry mouth, nausea, diarrhea, constipation, stomach pain
GU: urinary frequency, dysuria, changes in libido

Pregnancy Undefined

Lactation Undefined

NO BOXED WARNINGS

Principal riskBlood pressure and heart rate rise; short-term use only

Direct muscarinic antagonism0 / 4